Theologian and author; born at Lobsens, Posen, 1800; died in Berlin, 1886. He was destined for the rabbinate; but while attending the University of Berlin (1827-35) he made the acquaintance of the Oriental scholar Wilhelm Vatke, with whom he studied Christian theology. In 1837 he published "Auszüge aus dem Buche Sohar, mit Deutscher Uebersetzung," in which he tried to prove from Jewish literature the doctrine of the Trinity and other Christian dogmas.

The following year he was converted to Christianity, joined the Evangelical Church, and entered the service of the Jewish Mission of Berlin. In 1844 he became a member of the London Missionary Society, and engaged in missionary work among the Jews. His literary activity continued unabated.

Biesenthal's works, which give evidence of an extensive knowledge of rabbinical literature, and a thorough command of the Hebrew language, include: "Hebräisches und Chaldäisches Schulwörterbuch über das A. T." (1836-37); David Ḳimḥi's (in conjunction with F. S. Lebrecht), Berlin, 1838; "The Book of Psalms; Hebrew Text, with a Commentary," Berlin, 1841; "The Book of Isaiah; Hebrew Text and Commentary," Berlin, 1841; "Chrestomathia Rabbinica sive Libri Quatuor, Complectens Analećta e Rerum Scriptoribus, Cosmographis, Grammaticis, Exegetis, Philosophis, Cabalistis et Poetis, Partim e Codicibus Sumta, cum Versione Latina et Vitis Scriptorum," part i., Berlin, 1844;" Zur Geschichte der Christlichen Kirche in Ihrer Ersten Entwickelungsperiode bis zum Anfange des 4ten Jahrhunderts," in which he makes much use of Talmudical material, and endeavors to prove that the Jews stood in close connection with the early Christian Church; and a Hebrew translation of the Epistles to the Hebrews and the Romans, with a commentary based on rabbinical lore, and a biography of Paul, 1857-58.

In 1840, at the time of the blood accusation at Damascus, Biesenthal, under the name "Karl Ignaz Corvé," defended the Jews in his interesting work, "Ueber den Ursprung der Wider die Juden Erhobenen Beschuldigung bei der Feier Ihrer Ostern sich des Blutes zu Bedienen, Nebst Kurzer Darstellungdes Jüdischen Rituals in Beziehung auf den Genuss des Blutes," Berlin, 1840. Biesenthal received the degree of doctor of theology from the University of Giessen.